I always miss it because our visits to the States tend to be in the summer and the harvest is well after la rentrée when we are already back home safe and sound. Mom usually passes along a few pictures so we can vicariously experience the event but this year one of their friends went one step further and did a post for her blog Pacific Northwest Seasons. Great pictures and a fine description of the process which, yes, does involve sleeping in a tent, hard work, and getting down on one's hands and knees but also includes good cheer, fine wine, and tasty food. I cannot recommend enough the Silver Grille.
Here's the post: Down on the Farm: Willamette Valley Walnut Harvest
And here's one picture to add of a past harvest that I found recently in my archives. This is the patriarch Ben Jr. (Benjamin's father known to me and the Frenchlings as Grandpa Ben) at the farm. I recognize the handwriting on the back of the photo - it was taken by Grandma Benona (Ben Jr.'s wife) and she wrote, "Bringing in the last of the corn at the farm, 1984."
And here's what happens to all those walnuts after harvest: 2011 Harvest.